text: Chang et al., realized that further increase in resolution could be gained if one carefully analyzed the results of each spot detected by the CCD camera.  Under the microchannel plate amplification typical in most laboratories, each such spot was 5-10 pixels in diameter.  By programming a microprocessor to examine each of up to 200 spots per laser shot to determine the center of the distribution of each spot, Chang et al. were able to further increase the velocity resolution to the equivalent of one pixel out of the 256-pixel radius of the CCD chip.